So after some deciding and some bringing it up to the team. I've decided that while PNM is being removed, he'll be removed from being "Canon", allow me to explain.

PNM will still be replaced by the non-inverted Mickey, however, I'll be implementing a feature, a rewards system let's say that could tie into the custom night challenges. And one of those awards will be a Photo Negative Mickey skin for the Normal Mickey. Which allows you to replay the game with said chosen skin.

However, just cause PNM is being readded as a skin, does not imply he is Canon. He'll be a non-canon skin simply for the fans of Photo Negative Mickey. So keep that in mind.